1 | /**
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2 | * @file
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3 | * Address Resolution Protocol module for IP over Ethernet
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4 | *
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5 | * Functionally, ARP is divided into two parts. The first maps an IP address
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6 | * to a physical address when sending a packet, and the second part answers
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7 | * requests from other machines for our physical address.
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8 | *
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9 | * This implementation complies with RFC 826 (Ethernet ARP). It supports
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10 | * Gratuitious ARP from RFC3220 (IP Mobility Support for IPv4) section 4.6
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11 | * if an interface calls etharp_gratuitous(our_netif) upon address change.
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12 | */
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13 |
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14 | /*
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15 | * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
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16 | * Copyright (c) 2003-2004 Leon Woestenberg <leon.woestenberg@axon.tv>
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17 | * Copyright (c) 2003-2004 Axon Digital Design B.V., The Netherlands.
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18 | * All rights reserved.
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19 | *
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20 | * Redistribution and use in source and binary forms, with or without modification,
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21 | * are permitted provided that the following conditions are met:
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22 | *
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23 | * 1. Redistributions of source code must retain the above copyright notice,
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24 | * this list of conditions and the following disclaimer.
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25 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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26 | * this list of conditions and the following disclaimer in the documentation
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27 | * and/or other materials provided with the distribution.
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28 | * 3. The name of the author may not be used to endorse or promote products
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29 | * derived from this software without specific prior written permission.
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30 | *
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31 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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32 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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33 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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34 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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35 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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36 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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37 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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38 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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39 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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40 | * OF SUCH DAMAGE.
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41 | *
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42 | * This file is part of the lwIP TCP/IP stack.
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43 | *
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44 | */
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45 |
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46 | #include "lwip/opt.h"
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47 |
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48 | #if LWIP_IPV4 && LWIP_ARP /* don't build if not configured for use in lwipopts.h */
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49 |
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50 | #include "lwip/etharp.h"
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51 | #include "lwip/stats.h"
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52 | #include "lwip/snmp.h"
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53 | #include "lwip/dhcp.h"
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54 | #include "lwip/autoip.h"
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55 | #include "lwip/prot/iana.h"
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56 | #include "netif/ethernet.h"
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57 |
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58 | #include <string.h>
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59 |
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60 | #ifdef LWIP_HOOK_FILENAME
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61 | #include LWIP_HOOK_FILENAME
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62 | #endif
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63 |
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64 | /** Re-request a used ARP entry 1 minute before it would expire to prevent
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65 | * breaking a steadily used connection because the ARP entry timed out. */
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66 | #define ARP_AGE_REREQUEST_USED_UNICAST (ARP_MAXAGE - 30)
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67 | #define ARP_AGE_REREQUEST_USED_BROADCAST (ARP_MAXAGE - 15)
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68 |
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69 | /** the time an ARP entry stays pending after first request,
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70 | * for ARP_TMR_INTERVAL = 1000, this is
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71 | * 10 seconds.
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72 | *
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73 | * @internal Keep this number at least 2, otherwise it might
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74 | * run out instantly if the timeout occurs directly after a request.
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75 | */
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76 | #define ARP_MAXPENDING 5
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77 |
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78 | /** ARP states */
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79 | enum etharp_state {
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80 | ETHARP_STATE_EMPTY = 0,
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81 | ETHARP_STATE_PENDING,
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82 | ETHARP_STATE_STABLE,
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83 | ETHARP_STATE_STABLE_REREQUESTING_1,
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84 | ETHARP_STATE_STABLE_REREQUESTING_2
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85 | #if ETHARP_SUPPORT_STATIC_ENTRIES
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86 | , ETHARP_STATE_STATIC
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87 | #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
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88 | };
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89 |
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90 | struct etharp_entry {
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91 | #if ARP_QUEUEING
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92 | /** Pointer to queue of pending outgoing packets on this ARP entry. */
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93 | struct etharp_q_entry *q;
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94 | #else /* ARP_QUEUEING */
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95 | /** Pointer to a single pending outgoing packet on this ARP entry. */
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96 | struct pbuf *q;
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97 | #endif /* ARP_QUEUEING */
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98 | ip4_addr_t ipaddr;
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99 | struct netif *netif;
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100 | struct eth_addr ethaddr;
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101 | u16_t ctime;
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102 | u8_t state;
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103 | };
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104 |
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105 | static struct etharp_entry arp_table[ARP_TABLE_SIZE];
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106 |
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107 | #if !LWIP_NETIF_HWADDRHINT
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108 | static netif_addr_idx_t etharp_cached_entry;
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109 | #endif /* !LWIP_NETIF_HWADDRHINT */
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110 |
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111 | /** Try hard to create a new entry - we want the IP address to appear in
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112 | the cache (even if this means removing an active entry or so). */
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113 | #define ETHARP_FLAG_TRY_HARD 1
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114 | #define ETHARP_FLAG_FIND_ONLY 2
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115 | #if ETHARP_SUPPORT_STATIC_ENTRIES
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116 | #define ETHARP_FLAG_STATIC_ENTRY 4
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117 | #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
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118 |
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119 | #if LWIP_NETIF_HWADDRHINT
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120 | #define ETHARP_SET_ADDRHINT(netif, addrhint) do { if (((netif) != NULL) && ((netif)->hints != NULL)) { \
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121 | (netif)->hints->addr_hint = (addrhint); }} while(0)
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122 | #else /* LWIP_NETIF_HWADDRHINT */
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123 | #define ETHARP_SET_ADDRHINT(netif, addrhint) (etharp_cached_entry = (addrhint))
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124 | #endif /* LWIP_NETIF_HWADDRHINT */
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125 |
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126 |
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127 | /* Check for maximum ARP_TABLE_SIZE */
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128 | #if (ARP_TABLE_SIZE > NETIF_ADDR_IDX_MAX)
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129 | #error "ARP_TABLE_SIZE must fit in an s16_t, you have to reduce it in your lwipopts.h"
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130 | #endif
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131 |
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132 |
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133 | static err_t etharp_request_dst(struct netif *netif, const ip4_addr_t *ipaddr, const struct eth_addr *hw_dst_addr);
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134 | static err_t etharp_raw(struct netif *netif,
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135 | const struct eth_addr *ethsrc_addr, const struct eth_addr *ethdst_addr,
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136 | const struct eth_addr *hwsrc_addr, const ip4_addr_t *ipsrc_addr,
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137 | const struct eth_addr *hwdst_addr, const ip4_addr_t *ipdst_addr,
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138 | const u16_t opcode);
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139 |
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140 | #if ARP_QUEUEING
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141 | /**
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142 | * Free a complete queue of etharp entries
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143 | *
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144 | * @param q a qeueue of etharp_q_entry's to free
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145 | */
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146 | static void
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147 | free_etharp_q(struct etharp_q_entry *q)
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148 | {
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149 | struct etharp_q_entry *r;
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150 | LWIP_ASSERT("q != NULL", q != NULL);
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151 | while (q) {
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152 | r = q;
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153 | q = q->next;
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154 | LWIP_ASSERT("r->p != NULL", (r->p != NULL));
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155 | pbuf_free(r->p);
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156 | memp_free(MEMP_ARP_QUEUE, r);
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157 | }
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158 | }
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159 | #else /* ARP_QUEUEING */
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160 |
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161 | /** Compatibility define: free the queued pbuf */
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162 | #define free_etharp_q(q) pbuf_free(q)
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163 |
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164 | #endif /* ARP_QUEUEING */
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165 |
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166 | /** Clean up ARP table entries */
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167 | static void
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168 | etharp_free_entry(int i)
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169 | {
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170 | /* remove from SNMP ARP index tree */
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171 | mib2_remove_arp_entry(arp_table[i].netif, &arp_table[i].ipaddr);
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172 | /* and empty packet queue */
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173 | if (arp_table[i].q != NULL) {
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174 | /* remove all queued packets */
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175 | LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_free_entry: freeing entry %"U16_F", packet queue %p.\n", (u16_t)i, (void *)(arp_table[i].q)));
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176 | free_etharp_q(arp_table[i].q);
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177 | arp_table[i].q = NULL;
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178 | }
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179 | /* recycle entry for re-use */
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180 | arp_table[i].state = ETHARP_STATE_EMPTY;
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181 | #ifdef LWIP_DEBUG
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182 | /* for debugging, clean out the complete entry */
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183 | arp_table[i].ctime = 0;
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184 | arp_table[i].netif = NULL;
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185 | ip4_addr_set_zero(&arp_table[i].ipaddr);
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186 | arp_table[i].ethaddr = ethzero;
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187 | #endif /* LWIP_DEBUG */
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188 | }
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189 |
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190 | /**
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191 | * Clears expired entries in the ARP table.
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192 | *
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193 | * This function should be called every ARP_TMR_INTERVAL milliseconds (1 second),
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194 | * in order to expire entries in the ARP table.
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195 | */
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196 | void
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197 | etharp_tmr(void)
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198 | {
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199 | int i;
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200 |
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201 | LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer\n"));
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202 | /* remove expired entries from the ARP table */
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203 | for (i = 0; i < ARP_TABLE_SIZE; ++i) {
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204 | u8_t state = arp_table[i].state;
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205 | if (state != ETHARP_STATE_EMPTY
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206 | #if ETHARP_SUPPORT_STATIC_ENTRIES
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207 | && (state != ETHARP_STATE_STATIC)
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208 | #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
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209 | ) {
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210 | arp_table[i].ctime++;
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211 | if ((arp_table[i].ctime >= ARP_MAXAGE) ||
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212 | ((arp_table[i].state == ETHARP_STATE_PENDING) &&
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213 | (arp_table[i].ctime >= ARP_MAXPENDING))) {
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214 | /* pending or stable entry has become old! */
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215 | LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired %s entry %d.\n",
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216 | arp_table[i].state >= ETHARP_STATE_STABLE ? "stable" : "pending", i));
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217 | /* clean up entries that have just been expired */
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218 | etharp_free_entry(i);
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219 | } else if (arp_table[i].state == ETHARP_STATE_STABLE_REREQUESTING_1) {
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220 | /* Don't send more than one request every 2 seconds. */
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221 | arp_table[i].state = ETHARP_STATE_STABLE_REREQUESTING_2;
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222 | } else if (arp_table[i].state == ETHARP_STATE_STABLE_REREQUESTING_2) {
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223 | /* Reset state to stable, so that the next transmitted packet will
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224 | re-send an ARP request. */
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225 | arp_table[i].state = ETHARP_STATE_STABLE;
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226 | } else if (arp_table[i].state == ETHARP_STATE_PENDING) {
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227 | /* still pending, resend an ARP query */
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228 | etharp_request(arp_table[i].netif, &arp_table[i].ipaddr);
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229 | }
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230 | }
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231 | }
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232 | }
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233 |
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234 | /**
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235 | * Search the ARP table for a matching or new entry.
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236 | *
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237 | * If an IP address is given, return a pending or stable ARP entry that matches
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238 | * the address. If no match is found, create a new entry with this address set,
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239 | * but in state ETHARP_EMPTY. The caller must check and possibly change the
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240 | * state of the returned entry.
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241 | *
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242 | * If ipaddr is NULL, return a initialized new entry in state ETHARP_EMPTY.
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243 | *
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244 | * In all cases, attempt to create new entries from an empty entry. If no
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245 | * empty entries are available and ETHARP_FLAG_TRY_HARD flag is set, recycle
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246 | * old entries. Heuristic choose the least important entry for recycling.
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247 | *
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248 | * @param ipaddr IP address to find in ARP cache, or to add if not found.
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249 | * @param flags See @ref etharp_state
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250 | * @param netif netif related to this address (used for NETIF_HWADDRHINT)
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251 | *
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252 | * @return The ARP entry index that matched or is created, ERR_MEM if no
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253 | * entry is found or could be recycled.
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254 | */
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255 | static s16_t
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256 | etharp_find_entry(const ip4_addr_t *ipaddr, u8_t flags, struct netif *netif)
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257 | {
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258 | s16_t old_pending = ARP_TABLE_SIZE, old_stable = ARP_TABLE_SIZE;
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259 | s16_t empty = ARP_TABLE_SIZE;
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260 | s16_t i = 0;
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261 | /* oldest entry with packets on queue */
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262 | s16_t old_queue = ARP_TABLE_SIZE;
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263 | /* its age */
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264 | u16_t age_queue = 0, age_pending = 0, age_stable = 0;
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265 |
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266 | LWIP_UNUSED_ARG(netif);
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267 |
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268 | /**
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269 | * a) do a search through the cache, remember candidates
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270 | * b) select candidate entry
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271 | * c) create new entry
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272 | */
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273 |
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274 | /* a) in a single search sweep, do all of this
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275 | * 1) remember the first empty entry (if any)
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276 | * 2) remember the oldest stable entry (if any)
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277 | * 3) remember the oldest pending entry without queued packets (if any)
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278 | * 4) remember the oldest pending entry with queued packets (if any)
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279 | * 5) search for a matching IP entry, either pending or stable
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280 | * until 5 matches, or all entries are searched for.
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281 | */
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282 |
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283 | for (i = 0; i < ARP_TABLE_SIZE; ++i) {
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284 | u8_t state = arp_table[i].state;
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285 | /* no empty entry found yet and now we do find one? */
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286 | if ((empty == ARP_TABLE_SIZE) && (state == ETHARP_STATE_EMPTY)) {
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287 | LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_find_entry: found empty entry %d\n", (int)i));
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288 | /* remember first empty entry */
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289 | empty = i;
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290 | } else if (state != ETHARP_STATE_EMPTY) {
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291 | LWIP_ASSERT("state == ETHARP_STATE_PENDING || state >= ETHARP_STATE_STABLE",
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292 | state == ETHARP_STATE_PENDING || state >= ETHARP_STATE_STABLE);
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293 | /* if given, does IP address match IP address in ARP entry? */
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294 | if (ipaddr && ip4_addr_cmp(ipaddr, &arp_table[i].ipaddr)
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295 | #if ETHARP_TABLE_MATCH_NETIF
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296 | && ((netif == NULL) || (netif == arp_table[i].netif))
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297 | #endif /* ETHARP_TABLE_MATCH_NETIF */
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298 | ) {
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299 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: found matching entry %d\n", (int)i));
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300 | /* found exact IP address match, simply bail out */
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301 | return i;
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302 | }
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303 | /* pending entry? */
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304 | if (state == ETHARP_STATE_PENDING) {
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305 | /* pending with queued packets? */
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306 | if (arp_table[i].q != NULL) {
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307 | if (arp_table[i].ctime >= age_queue) {
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308 | old_queue = i;
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309 | age_queue = arp_table[i].ctime;
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310 | }
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311 | } else
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312 | /* pending without queued packets? */
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313 | {
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314 | if (arp_table[i].ctime >= age_pending) {
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315 | old_pending = i;
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316 | age_pending = arp_table[i].ctime;
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317 | }
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318 | }
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319 | /* stable entry? */
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320 | } else if (state >= ETHARP_STATE_STABLE) {
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321 | #if ETHARP_SUPPORT_STATIC_ENTRIES
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322 | /* don't record old_stable for static entries since they never expire */
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323 | if (state < ETHARP_STATE_STATIC)
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324 | #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
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325 | {
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326 | /* remember entry with oldest stable entry in oldest, its age in maxtime */
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327 | if (arp_table[i].ctime >= age_stable) {
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328 | old_stable = i;
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329 | age_stable = arp_table[i].ctime;
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330 | }
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331 | }
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332 | }
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333 | }
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334 | }
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335 | /* { we have no match } => try to create a new entry */
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336 |
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337 | /* don't create new entry, only search? */
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338 | if (((flags & ETHARP_FLAG_FIND_ONLY) != 0) ||
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339 | /* or no empty entry found and not allowed to recycle? */
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340 | ((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_FLAG_TRY_HARD) == 0))) {
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341 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: no empty entry found and not allowed to recycle\n"));
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342 | return (s16_t)ERR_MEM;
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343 | }
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344 |
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345 | /* b) choose the least destructive entry to recycle:
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346 | * 1) empty entry
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347 | * 2) oldest stable entry
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348 | * 3) oldest pending entry without queued packets
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349 | * 4) oldest pending entry with queued packets
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350 | *
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351 | * { ETHARP_FLAG_TRY_HARD is set at this point }
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352 | */
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353 |
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354 | /* 1) empty entry available? */
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355 | if (empty < ARP_TABLE_SIZE) {
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356 | i = empty;
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357 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting empty entry %d\n", (int)i));
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358 | } else {
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359 | /* 2) found recyclable stable entry? */
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360 | if (old_stable < ARP_TABLE_SIZE) {
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361 | /* recycle oldest stable*/
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362 | i = old_stable;
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363 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest stable entry %d\n", (int)i));
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364 | /* no queued packets should exist on stable entries */
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365 | LWIP_ASSERT("arp_table[i].q == NULL", arp_table[i].q == NULL);
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366 | /* 3) found recyclable pending entry without queued packets? */
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367 | } else if (old_pending < ARP_TABLE_SIZE) {
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368 | /* recycle oldest pending */
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369 | i = old_pending;
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370 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest pending entry %d (without queue)\n", (int)i));
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371 | /* 4) found recyclable pending entry with queued packets? */
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372 | } else if (old_queue < ARP_TABLE_SIZE) {
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373 | /* recycle oldest pending (queued packets are free in etharp_free_entry) */
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374 | i = old_queue;
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375 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest pending entry %d, freeing packet queue %p\n", (int)i, (void *)(arp_table[i].q)));
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376 | /* no empty or recyclable entries found */
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377 | } else {
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378 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: no empty or recyclable entries found\n"));
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379 | return (s16_t)ERR_MEM;
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380 | }
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381 |
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382 | /* { empty or recyclable entry found } */
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383 | LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
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384 | etharp_free_entry(i);
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385 | }
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386 |
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387 | LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
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388 | LWIP_ASSERT("arp_table[i].state == ETHARP_STATE_EMPTY",
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389 | arp_table[i].state == ETHARP_STATE_EMPTY);
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390 |
|
---|
391 | /* IP address given? */
|
---|
392 | if (ipaddr != NULL) {
|
---|
393 | /* set IP address */
|
---|
394 | ip4_addr_copy(arp_table[i].ipaddr, *ipaddr);
|
---|
395 | }
|
---|
396 | arp_table[i].ctime = 0;
|
---|
397 | #if ETHARP_TABLE_MATCH_NETIF
|
---|
398 | arp_table[i].netif = netif;
|
---|
399 | #endif /* ETHARP_TABLE_MATCH_NETIF */
|
---|
400 | return (s16_t)i;
|
---|
401 | }
|
---|
402 |
|
---|
403 | /**
|
---|
404 | * Update (or insert) a IP/MAC address pair in the ARP cache.
|
---|
405 | *
|
---|
406 | * If a pending entry is resolved, any queued packets will be sent
|
---|
407 | * at this point.
|
---|
408 | *
|
---|
409 | * @param netif netif related to this entry (used for NETIF_ADDRHINT)
|
---|
410 | * @param ipaddr IP address of the inserted ARP entry.
|
---|
411 | * @param ethaddr Ethernet address of the inserted ARP entry.
|
---|
412 | * @param flags See @ref etharp_state
|
---|
413 | *
|
---|
414 | * @return
|
---|
415 | * - ERR_OK Successfully updated ARP cache.
|
---|
416 | * - ERR_MEM If we could not add a new ARP entry when ETHARP_FLAG_TRY_HARD was set.
|
---|
417 | * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
|
---|
418 | *
|
---|
419 | * @see pbuf_free()
|
---|
420 | */
|
---|
421 | static err_t
|
---|
422 | etharp_update_arp_entry(struct netif *netif, const ip4_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags)
|
---|
423 | {
|
---|
424 | s16_t i;
|
---|
425 | LWIP_ASSERT("netif->hwaddr_len == ETH_HWADDR_LEN", netif->hwaddr_len == ETH_HWADDR_LEN);
|
---|
426 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_update_arp_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n",
|
---|
427 | ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
|
---|
428 | (u16_t)ethaddr->addr[0], (u16_t)ethaddr->addr[1], (u16_t)ethaddr->addr[2],
|
---|
429 | (u16_t)ethaddr->addr[3], (u16_t)ethaddr->addr[4], (u16_t)ethaddr->addr[5]));
|
---|
430 | /* non-unicast address? */
|
---|
431 | if (ip4_addr_isany(ipaddr) ||
|
---|
432 | ip4_addr_isbroadcast(ipaddr, netif) ||
|
---|
433 | ip4_addr_ismulticast(ipaddr)) {
|
---|
434 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_update_arp_entry: will not add non-unicast IP address to ARP cache\n"));
|
---|
435 | return ERR_ARG;
|
---|
436 | }
|
---|
437 | /* find or create ARP entry */
|
---|
438 | i = etharp_find_entry(ipaddr, flags, netif);
|
---|
439 | /* bail out if no entry could be found */
|
---|
440 | if (i < 0) {
|
---|
441 | return (err_t)i;
|
---|
442 | }
|
---|
443 |
|
---|
444 | #if ETHARP_SUPPORT_STATIC_ENTRIES
|
---|
445 | if (flags & ETHARP_FLAG_STATIC_ENTRY) {
|
---|
446 | /* record static type */
|
---|
447 | arp_table[i].state = ETHARP_STATE_STATIC;
|
---|
448 | } else if (arp_table[i].state == ETHARP_STATE_STATIC) {
|
---|
449 | /* found entry is a static type, don't overwrite it */
|
---|
450 | return ERR_VAL;
|
---|
451 | } else
|
---|
452 | #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
|
---|
453 | {
|
---|
454 | /* mark it stable */
|
---|
455 | arp_table[i].state = ETHARP_STATE_STABLE;
|
---|
456 | }
|
---|
457 |
|
---|
458 | /* record network interface */
|
---|
459 | arp_table[i].netif = netif;
|
---|
460 | /* insert in SNMP ARP index tree */
|
---|
461 | mib2_add_arp_entry(netif, &arp_table[i].ipaddr);
|
---|
462 |
|
---|
463 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_update_arp_entry: updating stable entry %"S16_F"\n", i));
|
---|
464 | /* update address */
|
---|
465 | SMEMCPY(&arp_table[i].ethaddr, ethaddr, ETH_HWADDR_LEN);
|
---|
466 | /* reset time stamp */
|
---|
467 | arp_table[i].ctime = 0;
|
---|
468 | /* this is where we will send out queued packets! */
|
---|
469 | #if ARP_QUEUEING
|
---|
470 | while (arp_table[i].q != NULL) {
|
---|
471 | struct pbuf *p;
|
---|
472 | /* remember remainder of queue */
|
---|
473 | struct etharp_q_entry *q = arp_table[i].q;
|
---|
474 | /* pop first item off the queue */
|
---|
475 | arp_table[i].q = q->next;
|
---|
476 | /* get the packet pointer */
|
---|
477 | p = q->p;
|
---|
478 | /* now queue entry can be freed */
|
---|
479 | memp_free(MEMP_ARP_QUEUE, q);
|
---|
480 | #else /* ARP_QUEUEING */
|
---|
481 | if (arp_table[i].q != NULL) {
|
---|
482 | struct pbuf *p = arp_table[i].q;
|
---|
483 | arp_table[i].q = NULL;
|
---|
484 | #endif /* ARP_QUEUEING */
|
---|
485 | /* send the queued IP packet */
|
---|
486 | ethernet_output(netif, p, (struct eth_addr *)(netif->hwaddr), ethaddr, ETHTYPE_IP);
|
---|
487 | /* free the queued IP packet */
|
---|
488 | pbuf_free(p);
|
---|
489 | }
|
---|
490 | return ERR_OK;
|
---|
491 | }
|
---|
492 |
|
---|
493 | #if ETHARP_SUPPORT_STATIC_ENTRIES
|
---|
494 | /** Add a new static entry to the ARP table. If an entry exists for the
|
---|
495 | * specified IP address, this entry is overwritten.
|
---|
496 | * If packets are queued for the specified IP address, they are sent out.
|
---|
497 | *
|
---|
498 | * @param ipaddr IP address for the new static entry
|
---|
499 | * @param ethaddr ethernet address for the new static entry
|
---|
500 | * @return See return values of etharp_add_static_entry
|
---|
501 | */
|
---|
502 | err_t
|
---|
503 | etharp_add_static_entry(const ip4_addr_t *ipaddr, struct eth_addr *ethaddr)
|
---|
504 | {
|
---|
505 | struct netif *netif;
|
---|
506 | LWIP_ASSERT_CORE_LOCKED();
|
---|
507 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_add_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n",
|
---|
508 | ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
|
---|
509 | (u16_t)ethaddr->addr[0], (u16_t)ethaddr->addr[1], (u16_t)ethaddr->addr[2],
|
---|
510 | (u16_t)ethaddr->addr[3], (u16_t)ethaddr->addr[4], (u16_t)ethaddr->addr[5]));
|
---|
511 |
|
---|
512 | netif = ip4_route(ipaddr);
|
---|
513 | if (netif == NULL) {
|
---|
514 | return ERR_RTE;
|
---|
515 | }
|
---|
516 |
|
---|
517 | return etharp_update_arp_entry(netif, ipaddr, ethaddr, ETHARP_FLAG_TRY_HARD | ETHARP_FLAG_STATIC_ENTRY);
|
---|
518 | }
|
---|
519 |
|
---|
520 | /** Remove a static entry from the ARP table previously added with a call to
|
---|
521 | * etharp_add_static_entry.
|
---|
522 | *
|
---|
523 | * @param ipaddr IP address of the static entry to remove
|
---|
524 | * @return ERR_OK: entry removed
|
---|
525 | * ERR_MEM: entry wasn't found
|
---|
526 | * ERR_ARG: entry wasn't a static entry but a dynamic one
|
---|
527 | */
|
---|
528 | err_t
|
---|
529 | etharp_remove_static_entry(const ip4_addr_t *ipaddr)
|
---|
530 | {
|
---|
531 | s16_t i;
|
---|
532 | LWIP_ASSERT_CORE_LOCKED();
|
---|
533 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_remove_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
|
---|
534 | ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
|
---|
535 |
|
---|
536 | /* find or create ARP entry */
|
---|
537 | i = etharp_find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY, NULL);
|
---|
538 | /* bail out if no entry could be found */
|
---|
539 | if (i < 0) {
|
---|
540 | return (err_t)i;
|
---|
541 | }
|
---|
542 |
|
---|
543 | if (arp_table[i].state != ETHARP_STATE_STATIC) {
|
---|
544 | /* entry wasn't a static entry, cannot remove it */
|
---|
545 | return ERR_ARG;
|
---|
546 | }
|
---|
547 | /* entry found, free it */
|
---|
548 | etharp_free_entry(i);
|
---|
549 | return ERR_OK;
|
---|
550 | }
|
---|
551 | #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
|
---|
552 |
|
---|
553 | /**
|
---|
554 | * Remove all ARP table entries of the specified netif.
|
---|
555 | *
|
---|
556 | * @param netif points to a network interface
|
---|
557 | */
|
---|
558 | void
|
---|
559 | etharp_cleanup_netif(struct netif *netif)
|
---|
560 | {
|
---|
561 | int i;
|
---|
562 |
|
---|
563 | for (i = 0; i < ARP_TABLE_SIZE; ++i) {
|
---|
564 | u8_t state = arp_table[i].state;
|
---|
565 | if ((state != ETHARP_STATE_EMPTY) && (arp_table[i].netif == netif)) {
|
---|
566 | etharp_free_entry(i);
|
---|
567 | }
|
---|
568 | }
|
---|
569 | }
|
---|
570 |
|
---|
571 | /**
|
---|
572 | * Finds (stable) ethernet/IP address pair from ARP table
|
---|
573 | * using interface and IP address index.
|
---|
574 | * @note the addresses in the ARP table are in network order!
|
---|
575 | *
|
---|
576 | * @param netif points to interface index
|
---|
577 | * @param ipaddr points to the (network order) IP address index
|
---|
578 | * @param eth_ret points to return pointer
|
---|
579 | * @param ip_ret points to return pointer
|
---|
580 | * @return table index if found, -1 otherwise
|
---|
581 | */
|
---|
582 | ssize_t
|
---|
583 | etharp_find_addr(struct netif *netif, const ip4_addr_t *ipaddr,
|
---|
584 | struct eth_addr **eth_ret, const ip4_addr_t **ip_ret)
|
---|
585 | {
|
---|
586 | s16_t i;
|
---|
587 |
|
---|
588 | LWIP_ASSERT("eth_ret != NULL && ip_ret != NULL",
|
---|
589 | eth_ret != NULL && ip_ret != NULL);
|
---|
590 |
|
---|
591 | LWIP_UNUSED_ARG(netif);
|
---|
592 |
|
---|
593 | i = etharp_find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY, netif);
|
---|
594 | if ((i >= 0) && (arp_table[i].state >= ETHARP_STATE_STABLE)) {
|
---|
595 | *eth_ret = &arp_table[i].ethaddr;
|
---|
596 | *ip_ret = &arp_table[i].ipaddr;
|
---|
597 | return i;
|
---|
598 | }
|
---|
599 | return -1;
|
---|
600 | }
|
---|
601 |
|
---|
602 | /**
|
---|
603 | * Possibility to iterate over stable ARP table entries
|
---|
604 | *
|
---|
605 | * @param i entry number, 0 to ARP_TABLE_SIZE
|
---|
606 | * @param ipaddr return value: IP address
|
---|
607 | * @param netif return value: points to interface
|
---|
608 | * @param eth_ret return value: ETH address
|
---|
609 | * @return 1 on valid index, 0 otherwise
|
---|
610 | */
|
---|
611 | int
|
---|
612 | etharp_get_entry(size_t i, ip4_addr_t **ipaddr, struct netif **netif, struct eth_addr **eth_ret)
|
---|
613 | {
|
---|
614 | LWIP_ASSERT("ipaddr != NULL", ipaddr != NULL);
|
---|
615 | LWIP_ASSERT("netif != NULL", netif != NULL);
|
---|
616 | LWIP_ASSERT("eth_ret != NULL", eth_ret != NULL);
|
---|
617 |
|
---|
618 | if ((i < ARP_TABLE_SIZE) && (arp_table[i].state >= ETHARP_STATE_STABLE)) {
|
---|
619 | *ipaddr = &arp_table[i].ipaddr;
|
---|
620 | *netif = arp_table[i].netif;
|
---|
621 | *eth_ret = &arp_table[i].ethaddr;
|
---|
622 | return 1;
|
---|
623 | } else {
|
---|
624 | return 0;
|
---|
625 | }
|
---|
626 | }
|
---|
627 |
|
---|
628 | /**
|
---|
629 | * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache
|
---|
630 | * send out queued IP packets. Updates cache with snooped address pairs.
|
---|
631 | *
|
---|
632 | * Should be called for incoming ARP packets. The pbuf in the argument
|
---|
633 | * is freed by this function.
|
---|
634 | *
|
---|
635 | * @param p The ARP packet that arrived on netif. Is freed by this function.
|
---|
636 | * @param netif The lwIP network interface on which the ARP packet pbuf arrived.
|
---|
637 | *
|
---|
638 | * @see pbuf_free()
|
---|
639 | */
|
---|
640 | void
|
---|
641 | etharp_input(struct pbuf *p, struct netif *netif)
|
---|
642 | {
|
---|
643 | struct etharp_hdr *hdr;
|
---|
644 | /* these are aligned properly, whereas the ARP header fields might not be */
|
---|
645 | ip4_addr_t sipaddr, dipaddr;
|
---|
646 | u8_t for_us;
|
---|
647 |
|
---|
648 | LWIP_ASSERT_CORE_LOCKED();
|
---|
649 |
|
---|
650 | LWIP_ERROR("netif != NULL", (netif != NULL), return;);
|
---|
651 |
|
---|
652 | hdr = (struct etharp_hdr *)p->payload;
|
---|
653 |
|
---|
654 | /* RFC 826 "Packet Reception": */
|
---|
655 | if ((hdr->hwtype != PP_HTONS(LWIP_IANA_HWTYPE_ETHERNET)) ||
|
---|
656 | (hdr->hwlen != ETH_HWADDR_LEN) ||
|
---|
657 | (hdr->protolen != sizeof(ip4_addr_t)) ||
|
---|
658 | (hdr->proto != PP_HTONS(ETHTYPE_IP))) {
|
---|
659 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
|
---|
660 | ("etharp_input: packet dropped, wrong hw type, hwlen, proto, protolen or ethernet type (%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n",
|
---|
661 | hdr->hwtype, (u16_t)hdr->hwlen, hdr->proto, (u16_t)hdr->protolen));
|
---|
662 | ETHARP_STATS_INC(etharp.proterr);
|
---|
663 | ETHARP_STATS_INC(etharp.drop);
|
---|
664 | pbuf_free(p);
|
---|
665 | return;
|
---|
666 | }
|
---|
667 | ETHARP_STATS_INC(etharp.recv);
|
---|
668 |
|
---|
669 | #if LWIP_AUTOIP
|
---|
670 | /* We have to check if a host already has configured our random
|
---|
671 | * created link local address and continuously check if there is
|
---|
672 | * a host with this IP-address so we can detect collisions */
|
---|
673 | autoip_arp_reply(netif, hdr);
|
---|
674 | #endif /* LWIP_AUTOIP */
|
---|
675 |
|
---|
676 | /* Copy struct ip4_addr_wordaligned to aligned ip4_addr, to support compilers without
|
---|
677 | * structure packing (not using structure copy which breaks strict-aliasing rules). */
|
---|
678 | IPADDR_WORDALIGNED_COPY_TO_IP4_ADDR_T(&sipaddr, &hdr->sipaddr);
|
---|
679 | IPADDR_WORDALIGNED_COPY_TO_IP4_ADDR_T(&dipaddr, &hdr->dipaddr);
|
---|
680 |
|
---|
681 | /* this interface is not configured? */
|
---|
682 | if (ip4_addr_isany_val(*netif_ip4_addr(netif))) {
|
---|
683 | for_us = 0;
|
---|
684 | } else {
|
---|
685 | /* ARP packet directed to us? */
|
---|
686 | for_us = (u8_t)ip4_addr_cmp(&dipaddr, netif_ip4_addr(netif));
|
---|
687 | }
|
---|
688 |
|
---|
689 | /* ARP message directed to us?
|
---|
690 | -> add IP address in ARP cache; assume requester wants to talk to us,
|
---|
691 | can result in directly sending the queued packets for this host.
|
---|
692 | ARP message not directed to us?
|
---|
693 | -> update the source IP address in the cache, if present */
|
---|
694 | etharp_update_arp_entry(netif, &sipaddr, &(hdr->shwaddr),
|
---|
695 | for_us ? ETHARP_FLAG_TRY_HARD : ETHARP_FLAG_FIND_ONLY);
|
---|
696 |
|
---|
697 | /* now act on the message itself */
|
---|
698 | switch (hdr->opcode) {
|
---|
699 | /* ARP request? */
|
---|
700 | case PP_HTONS(ARP_REQUEST):
|
---|
701 | /* ARP request. If it asked for our address, we send out a
|
---|
702 | * reply. In any case, we time-stamp any existing ARP entry,
|
---|
703 | * and possibly send out an IP packet that was queued on it. */
|
---|
704 |
|
---|
705 | LWIP_DEBUGF (ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: incoming ARP request\n"));
|
---|
706 | /* ARP request for our address? */
|
---|
707 | if (for_us) {
|
---|
708 | /* send ARP response */
|
---|
709 | etharp_raw(netif,
|
---|
710 | (struct eth_addr *)netif->hwaddr, &hdr->shwaddr,
|
---|
711 | (struct eth_addr *)netif->hwaddr, netif_ip4_addr(netif),
|
---|
712 | &hdr->shwaddr, &sipaddr,
|
---|
713 | ARP_REPLY);
|
---|
714 | /* we are not configured? */
|
---|
715 | } else if (ip4_addr_isany_val(*netif_ip4_addr(netif))) {
|
---|
716 | /* { for_us == 0 and netif->ip_addr.addr == 0 } */
|
---|
717 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: we are unconfigured, ARP request ignored.\n"));
|
---|
718 | /* request was not directed to us */
|
---|
719 | } else {
|
---|
720 | /* { for_us == 0 and netif->ip_addr.addr != 0 } */
|
---|
721 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: ARP request was not for us.\n"));
|
---|
722 | }
|
---|
723 | break;
|
---|
724 | case PP_HTONS(ARP_REPLY):
|
---|
725 | /* ARP reply. We already updated the ARP cache earlier. */
|
---|
726 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: incoming ARP reply\n"));
|
---|
727 | #if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
|
---|
728 | /* DHCP wants to know about ARP replies from any host with an
|
---|
729 | * IP address also offered to us by the DHCP server. We do not
|
---|
730 | * want to take a duplicate IP address on a single network.
|
---|
731 | * @todo How should we handle redundant (fail-over) interfaces? */
|
---|
732 | dhcp_arp_reply(netif, &sipaddr);
|
---|
733 | #endif /* (LWIP_DHCP && DHCP_DOES_ARP_CHECK) */
|
---|
734 | break;
|
---|
735 | default:
|
---|
736 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: ARP unknown opcode type %"S16_F"\n", lwip_htons(hdr->opcode)));
|
---|
737 | ETHARP_STATS_INC(etharp.err);
|
---|
738 | break;
|
---|
739 | }
|
---|
740 | /* free ARP packet */
|
---|
741 | pbuf_free(p);
|
---|
742 | }
|
---|
743 |
|
---|
744 | /** Just a small helper function that sends a pbuf to an ethernet address
|
---|
745 | * in the arp_table specified by the index 'arp_idx'.
|
---|
746 | */
|
---|
747 | static err_t
|
---|
748 | etharp_output_to_arp_index(struct netif *netif, struct pbuf *q, netif_addr_idx_t arp_idx)
|
---|
749 | {
|
---|
750 | LWIP_ASSERT("arp_table[arp_idx].state >= ETHARP_STATE_STABLE",
|
---|
751 | arp_table[arp_idx].state >= ETHARP_STATE_STABLE);
|
---|
752 | /* if arp table entry is about to expire: re-request it,
|
---|
753 | but only if its state is ETHARP_STATE_STABLE to prevent flooding the
|
---|
754 | network with ARP requests if this address is used frequently. */
|
---|
755 | if (arp_table[arp_idx].state == ETHARP_STATE_STABLE) {
|
---|
756 | if (arp_table[arp_idx].ctime >= ARP_AGE_REREQUEST_USED_BROADCAST) {
|
---|
757 | /* issue a standard request using broadcast */
|
---|
758 | if (etharp_request(netif, &arp_table[arp_idx].ipaddr) == ERR_OK) {
|
---|
759 | arp_table[arp_idx].state = ETHARP_STATE_STABLE_REREQUESTING_1;
|
---|
760 | }
|
---|
761 | } else if (arp_table[arp_idx].ctime >= ARP_AGE_REREQUEST_USED_UNICAST) {
|
---|
762 | /* issue a unicast request (for 15 seconds) to prevent unnecessary broadcast */
|
---|
763 | if (etharp_request_dst(netif, &arp_table[arp_idx].ipaddr, &arp_table[arp_idx].ethaddr) == ERR_OK) {
|
---|
764 | arp_table[arp_idx].state = ETHARP_STATE_STABLE_REREQUESTING_1;
|
---|
765 | }
|
---|
766 | }
|
---|
767 | }
|
---|
768 |
|
---|
769 | return ethernet_output(netif, q, (struct eth_addr *)(netif->hwaddr), &arp_table[arp_idx].ethaddr, ETHTYPE_IP);
|
---|
770 | }
|
---|
771 |
|
---|
772 | /**
|
---|
773 | * Resolve and fill-in Ethernet address header for outgoing IP packet.
|
---|
774 | *
|
---|
775 | * For IP multicast and broadcast, corresponding Ethernet addresses
|
---|
776 | * are selected and the packet is transmitted on the link.
|
---|
777 | *
|
---|
778 | * For unicast addresses, the packet is submitted to etharp_query(). In
|
---|
779 | * case the IP address is outside the local network, the IP address of
|
---|
780 | * the gateway is used.
|
---|
781 | *
|
---|
782 | * @param netif The lwIP network interface which the IP packet will be sent on.
|
---|
783 | * @param q The pbuf(s) containing the IP packet to be sent.
|
---|
784 | * @param ipaddr The IP address of the packet destination.
|
---|
785 | *
|
---|
786 | * @return
|
---|
787 | * - ERR_RTE No route to destination (no gateway to external networks),
|
---|
788 | * or the return type of either etharp_query() or ethernet_output().
|
---|
789 | */
|
---|
790 | err_t
|
---|
791 | etharp_output(struct netif *netif, struct pbuf *q, const ip4_addr_t *ipaddr)
|
---|
792 | {
|
---|
793 | const struct eth_addr *dest;
|
---|
794 | struct eth_addr mcastaddr;
|
---|
795 | const ip4_addr_t *dst_addr = ipaddr;
|
---|
796 |
|
---|
797 | LWIP_ASSERT_CORE_LOCKED();
|
---|
798 | LWIP_ASSERT("netif != NULL", netif != NULL);
|
---|
799 | LWIP_ASSERT("q != NULL", q != NULL);
|
---|
800 | LWIP_ASSERT("ipaddr != NULL", ipaddr != NULL);
|
---|
801 |
|
---|
802 | /* Determine on destination hardware address. Broadcasts and multicasts
|
---|
803 | * are special, other IP addresses are looked up in the ARP table. */
|
---|
804 |
|
---|
805 | /* broadcast destination IP address? */
|
---|
806 | if (ip4_addr_isbroadcast(ipaddr, netif)) {
|
---|
807 | /* broadcast on Ethernet also */
|
---|
808 | dest = (const struct eth_addr *)ðbroadcast;
|
---|
809 | /* multicast destination IP address? */
|
---|
810 | } else if (ip4_addr_ismulticast(ipaddr)) {
|
---|
811 | /* Hash IP multicast address to MAC address.*/
|
---|
812 | mcastaddr.addr[0] = LL_IP4_MULTICAST_ADDR_0;
|
---|
813 | mcastaddr.addr[1] = LL_IP4_MULTICAST_ADDR_1;
|
---|
814 | mcastaddr.addr[2] = LL_IP4_MULTICAST_ADDR_2;
|
---|
815 | mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f;
|
---|
816 | mcastaddr.addr[4] = ip4_addr3(ipaddr);
|
---|
817 | mcastaddr.addr[5] = ip4_addr4(ipaddr);
|
---|
818 | /* destination Ethernet address is multicast */
|
---|
819 | dest = &mcastaddr;
|
---|
820 | /* unicast destination IP address? */
|
---|
821 | } else {
|
---|
822 | netif_addr_idx_t i;
|
---|
823 | /* outside local network? if so, this can neither be a global broadcast nor
|
---|
824 | a subnet broadcast. */
|
---|
825 | if (!ip4_addr_netcmp(ipaddr, netif_ip4_addr(netif), netif_ip4_netmask(netif)) &&
|
---|
826 | !ip4_addr_islinklocal(ipaddr)) {
|
---|
827 | #if LWIP_AUTOIP
|
---|
828 | struct ip_hdr *iphdr = LWIP_ALIGNMENT_CAST(struct ip_hdr *, q->payload);
|
---|
829 | /* According to RFC 3297, chapter 2.6.2 (Forwarding Rules), a packet with
|
---|
830 | a link-local source address must always be "directly to its destination
|
---|
831 | on the same physical link. The host MUST NOT send the packet to any
|
---|
832 | router for forwarding". */
|
---|
833 | if (!ip4_addr_islinklocal(&iphdr->src))
|
---|
834 | #endif /* LWIP_AUTOIP */
|
---|
835 | {
|
---|
836 | #ifdef LWIP_HOOK_ETHARP_GET_GW
|
---|
837 | /* For advanced routing, a single default gateway might not be enough, so get
|
---|
838 | the IP address of the gateway to handle the current destination address. */
|
---|
839 | dst_addr = LWIP_HOOK_ETHARP_GET_GW(netif, ipaddr);
|
---|
840 | if (dst_addr == NULL)
|
---|
841 | #endif /* LWIP_HOOK_ETHARP_GET_GW */
|
---|
842 | {
|
---|
843 | /* interface has default gateway? */
|
---|
844 | if (!ip4_addr_isany_val(*netif_ip4_gw(netif))) {
|
---|
845 | /* send to hardware address of default gateway IP address */
|
---|
846 | dst_addr = netif_ip4_gw(netif);
|
---|
847 | /* no default gateway available */
|
---|
848 | } else {
|
---|
849 | /* no route to destination error (default gateway missing) */
|
---|
850 | return ERR_RTE;
|
---|
851 | }
|
---|
852 | }
|
---|
853 | }
|
---|
854 | }
|
---|
855 | #if LWIP_NETIF_HWADDRHINT
|
---|
856 | if (netif->hints != NULL) {
|
---|
857 | /* per-pcb cached entry was given */
|
---|
858 | netif_addr_idx_t etharp_cached_entry = netif->hints->addr_hint;
|
---|
859 | if (etharp_cached_entry < ARP_TABLE_SIZE) {
|
---|
860 | #endif /* LWIP_NETIF_HWADDRHINT */
|
---|
861 | if ((arp_table[etharp_cached_entry].state >= ETHARP_STATE_STABLE) &&
|
---|
862 | #if ETHARP_TABLE_MATCH_NETIF
|
---|
863 | (arp_table[etharp_cached_entry].netif == netif) &&
|
---|
864 | #endif
|
---|
865 | (ip4_addr_cmp(dst_addr, &arp_table[etharp_cached_entry].ipaddr))) {
|
---|
866 | /* the per-pcb-cached entry is stable and the right one! */
|
---|
867 | ETHARP_STATS_INC(etharp.cachehit);
|
---|
868 | return etharp_output_to_arp_index(netif, q, etharp_cached_entry);
|
---|
869 | }
|
---|
870 | #if LWIP_NETIF_HWADDRHINT
|
---|
871 | }
|
---|
872 | }
|
---|
873 | #endif /* LWIP_NETIF_HWADDRHINT */
|
---|
874 |
|
---|
875 | /* find stable entry: do this here since this is a critical path for
|
---|
876 | throughput and etharp_find_entry() is kind of slow */
|
---|
877 | for (i = 0; i < ARP_TABLE_SIZE; i++) {
|
---|
878 | if ((arp_table[i].state >= ETHARP_STATE_STABLE) &&
|
---|
879 | #if ETHARP_TABLE_MATCH_NETIF
|
---|
880 | (arp_table[i].netif == netif) &&
|
---|
881 | #endif
|
---|
882 | (ip4_addr_cmp(dst_addr, &arp_table[i].ipaddr))) {
|
---|
883 | /* found an existing, stable entry */
|
---|
884 | ETHARP_SET_ADDRHINT(netif, i);
|
---|
885 | return etharp_output_to_arp_index(netif, q, i);
|
---|
886 | }
|
---|
887 | }
|
---|
888 | /* no stable entry found, use the (slower) query function:
|
---|
889 | queue on destination Ethernet address belonging to ipaddr */
|
---|
890 | return etharp_query(netif, dst_addr, q);
|
---|
891 | }
|
---|
892 |
|
---|
893 | /* continuation for multicast/broadcast destinations */
|
---|
894 | /* obtain source Ethernet address of the given interface */
|
---|
895 | /* send packet directly on the link */
|
---|
896 | return ethernet_output(netif, q, (struct eth_addr *)(netif->hwaddr), dest, ETHTYPE_IP);
|
---|
897 | }
|
---|
898 |
|
---|
899 | /**
|
---|
900 | * Send an ARP request for the given IP address and/or queue a packet.
|
---|
901 | *
|
---|
902 | * If the IP address was not yet in the cache, a pending ARP cache entry
|
---|
903 | * is added and an ARP request is sent for the given address. The packet
|
---|
904 | * is queued on this entry.
|
---|
905 | *
|
---|
906 | * If the IP address was already pending in the cache, a new ARP request
|
---|
907 | * is sent for the given address. The packet is queued on this entry.
|
---|
908 | *
|
---|
909 | * If the IP address was already stable in the cache, and a packet is
|
---|
910 | * given, it is directly sent and no ARP request is sent out.
|
---|
911 | *
|
---|
912 | * If the IP address was already stable in the cache, and no packet is
|
---|
913 | * given, an ARP request is sent out.
|
---|
914 | *
|
---|
915 | * @param netif The lwIP network interface on which ipaddr
|
---|
916 | * must be queried for.
|
---|
917 | * @param ipaddr The IP address to be resolved.
|
---|
918 | * @param q If non-NULL, a pbuf that must be delivered to the IP address.
|
---|
919 | * q is not freed by this function.
|
---|
920 | *
|
---|
921 | * @note q must only be ONE packet, not a packet queue!
|
---|
922 | *
|
---|
923 | * @return
|
---|
924 | * - ERR_BUF Could not make room for Ethernet header.
|
---|
925 | * - ERR_MEM Hardware address unknown, and no more ARP entries available
|
---|
926 | * to query for address or queue the packet.
|
---|
927 | * - ERR_MEM Could not queue packet due to memory shortage.
|
---|
928 | * - ERR_RTE No route to destination (no gateway to external networks).
|
---|
929 | * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
|
---|
930 | *
|
---|
931 | */
|
---|
932 | err_t
|
---|
933 | etharp_query(struct netif *netif, const ip4_addr_t *ipaddr, struct pbuf *q)
|
---|
934 | {
|
---|
935 | struct eth_addr *srcaddr = (struct eth_addr *)netif->hwaddr;
|
---|
936 | err_t result = ERR_MEM;
|
---|
937 | int is_new_entry = 0;
|
---|
938 | s16_t i_err;
|
---|
939 | netif_addr_idx_t i;
|
---|
940 |
|
---|
941 | /* non-unicast address? */
|
---|
942 | if (ip4_addr_isbroadcast(ipaddr, netif) ||
|
---|
943 | ip4_addr_ismulticast(ipaddr) ||
|
---|
944 | ip4_addr_isany(ipaddr)) {
|
---|
945 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: will not add non-unicast IP address to ARP cache\n"));
|
---|
946 | return ERR_ARG;
|
---|
947 | }
|
---|
948 |
|
---|
949 | /* find entry in ARP cache, ask to create entry if queueing packet */
|
---|
950 | i_err = etharp_find_entry(ipaddr, ETHARP_FLAG_TRY_HARD, netif);
|
---|
951 |
|
---|
952 | /* could not find or create entry? */
|
---|
953 | if (i_err < 0) {
|
---|
954 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not create ARP entry\n"));
|
---|
955 | if (q) {
|
---|
956 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: packet dropped\n"));
|
---|
957 | ETHARP_STATS_INC(etharp.memerr);
|
---|
958 | }
|
---|
959 | return (err_t)i_err;
|
---|
960 | }
|
---|
961 | LWIP_ASSERT("type overflow", (size_t)i_err < NETIF_ADDR_IDX_MAX);
|
---|
962 | i = (netif_addr_idx_t)i_err;
|
---|
963 |
|
---|
964 | /* mark a fresh entry as pending (we just sent a request) */
|
---|
965 | if (arp_table[i].state == ETHARP_STATE_EMPTY) {
|
---|
966 | is_new_entry = 1;
|
---|
967 | arp_table[i].state = ETHARP_STATE_PENDING;
|
---|
968 | /* record network interface for re-sending arp request in etharp_tmr */
|
---|
969 | arp_table[i].netif = netif;
|
---|
970 | }
|
---|
971 |
|
---|
972 | /* { i is either a STABLE or (new or existing) PENDING entry } */
|
---|
973 | LWIP_ASSERT("arp_table[i].state == PENDING or STABLE",
|
---|
974 | ((arp_table[i].state == ETHARP_STATE_PENDING) ||
|
---|
975 | (arp_table[i].state >= ETHARP_STATE_STABLE)));
|
---|
976 |
|
---|
977 | /* do we have a new entry? or an implicit query request? */
|
---|
978 | if (is_new_entry || (q == NULL)) {
|
---|
979 | /* try to resolve it; send out ARP request */
|
---|
980 | result = etharp_request(netif, ipaddr);
|
---|
981 | if (result != ERR_OK) {
|
---|
982 | /* ARP request couldn't be sent */
|
---|
983 | /* We don't re-send arp request in etharp_tmr, but we still queue packets,
|
---|
984 | since this failure could be temporary, and the next packet calling
|
---|
985 | etharp_query again could lead to sending the queued packets. */
|
---|
986 | }
|
---|
987 | if (q == NULL) {
|
---|
988 | return result;
|
---|
989 | }
|
---|
990 | }
|
---|
991 |
|
---|
992 | /* packet given? */
|
---|
993 | LWIP_ASSERT("q != NULL", q != NULL);
|
---|
994 | /* stable entry? */
|
---|
995 | if (arp_table[i].state >= ETHARP_STATE_STABLE) {
|
---|
996 | /* we have a valid IP->Ethernet address mapping */
|
---|
997 | ETHARP_SET_ADDRHINT(netif, i);
|
---|
998 | /* send the packet */
|
---|
999 | result = ethernet_output(netif, q, srcaddr, &(arp_table[i].ethaddr), ETHTYPE_IP);
|
---|
1000 | /* pending entry? (either just created or already pending */
|
---|
1001 | } else if (arp_table[i].state == ETHARP_STATE_PENDING) {
|
---|
1002 | /* entry is still pending, queue the given packet 'q' */
|
---|
1003 | struct pbuf *p;
|
---|
1004 | int copy_needed = 0;
|
---|
1005 | /* IF q includes a pbuf that must be copied, copy the whole chain into a
|
---|
1006 | * new PBUF_RAM. See the definition of PBUF_NEEDS_COPY for details. */
|
---|
1007 | p = q;
|
---|
1008 | while (p) {
|
---|
1009 | LWIP_ASSERT("no packet queues allowed!", (p->len != p->tot_len) || (p->next == 0));
|
---|
1010 | if (PBUF_NEEDS_COPY(p)) {
|
---|
1011 | copy_needed = 1;
|
---|
1012 | break;
|
---|
1013 | }
|
---|
1014 | p = p->next;
|
---|
1015 | }
|
---|
1016 | if (copy_needed) {
|
---|
1017 | /* copy the whole packet into new pbufs */
|
---|
1018 | p = pbuf_clone(PBUF_LINK, PBUF_RAM, q);
|
---|
1019 | } else {
|
---|
1020 | /* referencing the old pbuf is enough */
|
---|
1021 | p = q;
|
---|
1022 | pbuf_ref(p);
|
---|
1023 | }
|
---|
1024 | /* packet could be taken over? */
|
---|
1025 | if (p != NULL) {
|
---|
1026 | /* queue packet ... */
|
---|
1027 | #if ARP_QUEUEING
|
---|
1028 | struct etharp_q_entry *new_entry;
|
---|
1029 | /* allocate a new arp queue entry */
|
---|
1030 | new_entry = (struct etharp_q_entry *)memp_malloc(MEMP_ARP_QUEUE);
|
---|
1031 | if (new_entry != NULL) {
|
---|
1032 | unsigned int qlen = 0;
|
---|
1033 | new_entry->next = 0;
|
---|
1034 | new_entry->p = p;
|
---|
1035 | if (arp_table[i].q != NULL) {
|
---|
1036 | /* queue was already existent, append the new entry to the end */
|
---|
1037 | struct etharp_q_entry *r;
|
---|
1038 | r = arp_table[i].q;
|
---|
1039 | qlen++;
|
---|
1040 | while (r->next != NULL) {
|
---|
1041 | r = r->next;
|
---|
1042 | qlen++;
|
---|
1043 | }
|
---|
1044 | r->next = new_entry;
|
---|
1045 | } else {
|
---|
1046 | /* queue did not exist, first item in queue */
|
---|
1047 | arp_table[i].q = new_entry;
|
---|
1048 | }
|
---|
1049 | #if ARP_QUEUE_LEN
|
---|
1050 | if (qlen >= ARP_QUEUE_LEN) {
|
---|
1051 | struct etharp_q_entry *old;
|
---|
1052 | old = arp_table[i].q;
|
---|
1053 | arp_table[i].q = arp_table[i].q->next;
|
---|
1054 | pbuf_free(old->p);
|
---|
1055 | memp_free(MEMP_ARP_QUEUE, old);
|
---|
1056 | }
|
---|
1057 | #endif
|
---|
1058 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"U16_F"\n", (void *)q, i));
|
---|
1059 | result = ERR_OK;
|
---|
1060 | } else {
|
---|
1061 | /* the pool MEMP_ARP_QUEUE is empty */
|
---|
1062 | pbuf_free(p);
|
---|
1063 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q));
|
---|
1064 | result = ERR_MEM;
|
---|
1065 | }
|
---|
1066 | #else /* ARP_QUEUEING */
|
---|
1067 | /* always queue one packet per ARP request only, freeing a previously queued packet */
|
---|
1068 | if (arp_table[i].q != NULL) {
|
---|
1069 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: dropped previously queued packet %p for ARP entry %"U16_F"\n", (void *)q, (u16_t)i));
|
---|
1070 | pbuf_free(arp_table[i].q);
|
---|
1071 | }
|
---|
1072 | arp_table[i].q = p;
|
---|
1073 | result = ERR_OK;
|
---|
1074 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"U16_F"\n", (void *)q, (u16_t)i));
|
---|
1075 | #endif /* ARP_QUEUEING */
|
---|
1076 | } else {
|
---|
1077 | ETHARP_STATS_INC(etharp.memerr);
|
---|
1078 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q));
|
---|
1079 | result = ERR_MEM;
|
---|
1080 | }
|
---|
1081 | }
|
---|
1082 | return result;
|
---|
1083 | }
|
---|
1084 |
|
---|
1085 | /**
|
---|
1086 | * Send a raw ARP packet (opcode and all addresses can be modified)
|
---|
1087 | *
|
---|
1088 | * @param netif the lwip network interface on which to send the ARP packet
|
---|
1089 | * @param ethsrc_addr the source MAC address for the ethernet header
|
---|
1090 | * @param ethdst_addr the destination MAC address for the ethernet header
|
---|
1091 | * @param hwsrc_addr the source MAC address for the ARP protocol header
|
---|
1092 | * @param ipsrc_addr the source IP address for the ARP protocol header
|
---|
1093 | * @param hwdst_addr the destination MAC address for the ARP protocol header
|
---|
1094 | * @param ipdst_addr the destination IP address for the ARP protocol header
|
---|
1095 | * @param opcode the type of the ARP packet
|
---|
1096 | * @return ERR_OK if the ARP packet has been sent
|
---|
1097 | * ERR_MEM if the ARP packet couldn't be allocated
|
---|
1098 | * any other err_t on failure
|
---|
1099 | */
|
---|
1100 | static err_t
|
---|
1101 | etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr,
|
---|
1102 | const struct eth_addr *ethdst_addr,
|
---|
1103 | const struct eth_addr *hwsrc_addr, const ip4_addr_t *ipsrc_addr,
|
---|
1104 | const struct eth_addr *hwdst_addr, const ip4_addr_t *ipdst_addr,
|
---|
1105 | const u16_t opcode)
|
---|
1106 | {
|
---|
1107 | struct pbuf *p;
|
---|
1108 | err_t result = ERR_OK;
|
---|
1109 | struct etharp_hdr *hdr;
|
---|
1110 |
|
---|
1111 | LWIP_ASSERT("netif != NULL", netif != NULL);
|
---|
1112 |
|
---|
1113 | /* allocate a pbuf for the outgoing ARP request packet */
|
---|
1114 | p = pbuf_alloc(PBUF_LINK, SIZEOF_ETHARP_HDR, PBUF_RAM);
|
---|
1115 | /* could allocate a pbuf for an ARP request? */
|
---|
1116 | if (p == NULL) {
|
---|
1117 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
|
---|
1118 | ("etharp_raw: could not allocate pbuf for ARP request.\n"));
|
---|
1119 | ETHARP_STATS_INC(etharp.memerr);
|
---|
1120 | return ERR_MEM;
|
---|
1121 | }
|
---|
1122 | LWIP_ASSERT("check that first pbuf can hold struct etharp_hdr",
|
---|
1123 | (p->len >= SIZEOF_ETHARP_HDR));
|
---|
1124 |
|
---|
1125 | hdr = (struct etharp_hdr *)p->payload;
|
---|
1126 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_raw: sending raw ARP packet.\n"));
|
---|
1127 | hdr->opcode = lwip_htons(opcode);
|
---|
1128 |
|
---|
1129 | LWIP_ASSERT("netif->hwaddr_len must be the same as ETH_HWADDR_LEN for etharp!",
|
---|
1130 | (netif->hwaddr_len == ETH_HWADDR_LEN));
|
---|
1131 |
|
---|
1132 | /* Write the ARP MAC-Addresses */
|
---|
1133 | SMEMCPY(&hdr->shwaddr, hwsrc_addr, ETH_HWADDR_LEN);
|
---|
1134 | SMEMCPY(&hdr->dhwaddr, hwdst_addr, ETH_HWADDR_LEN);
|
---|
1135 | /* Copy struct ip4_addr_wordaligned to aligned ip4_addr, to support compilers without
|
---|
1136 | * structure packing. */
|
---|
1137 | IPADDR_WORDALIGNED_COPY_FROM_IP4_ADDR_T(&hdr->sipaddr, ipsrc_addr);
|
---|
1138 | IPADDR_WORDALIGNED_COPY_FROM_IP4_ADDR_T(&hdr->dipaddr, ipdst_addr);
|
---|
1139 |
|
---|
1140 | hdr->hwtype = PP_HTONS(LWIP_IANA_HWTYPE_ETHERNET);
|
---|
1141 | hdr->proto = PP_HTONS(ETHTYPE_IP);
|
---|
1142 | /* set hwlen and protolen */
|
---|
1143 | hdr->hwlen = ETH_HWADDR_LEN;
|
---|
1144 | hdr->protolen = sizeof(ip4_addr_t);
|
---|
1145 |
|
---|
1146 | /* send ARP query */
|
---|
1147 | #if LWIP_AUTOIP
|
---|
1148 | /* If we are using Link-Local, all ARP packets that contain a Link-Local
|
---|
1149 | * 'sender IP address' MUST be sent using link-layer broadcast instead of
|
---|
1150 | * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */
|
---|
1151 | if (ip4_addr_islinklocal(ipsrc_addr)) {
|
---|
1152 | ethernet_output(netif, p, ethsrc_addr, ðbroadcast, ETHTYPE_ARP);
|
---|
1153 | } else
|
---|
1154 | #endif /* LWIP_AUTOIP */
|
---|
1155 | {
|
---|
1156 | ethernet_output(netif, p, ethsrc_addr, ethdst_addr, ETHTYPE_ARP);
|
---|
1157 | }
|
---|
1158 |
|
---|
1159 | ETHARP_STATS_INC(etharp.xmit);
|
---|
1160 | /* free ARP query packet */
|
---|
1161 | pbuf_free(p);
|
---|
1162 | p = NULL;
|
---|
1163 | /* could not allocate pbuf for ARP request */
|
---|
1164 |
|
---|
1165 | return result;
|
---|
1166 | }
|
---|
1167 |
|
---|
1168 | /**
|
---|
1169 | * Send an ARP request packet asking for ipaddr to a specific eth address.
|
---|
1170 | * Used to send unicast request to refresh the ARP table just before an entry
|
---|
1171 | * times out
|
---|
1172 | *
|
---|
1173 | * @param netif the lwip network interface on which to send the request
|
---|
1174 | * @param ipaddr the IP address for which to ask
|
---|
1175 | * @param hw_dst_addr the ethernet address to send this packet to
|
---|
1176 | * @return ERR_OK if the request has been sent
|
---|
1177 | * ERR_MEM if the ARP packet couldn't be allocated
|
---|
1178 | * any other err_t on failure
|
---|
1179 | */
|
---|
1180 | static err_t
|
---|
1181 | etharp_request_dst(struct netif *netif, const ip4_addr_t *ipaddr, const struct eth_addr *hw_dst_addr)
|
---|
1182 | {
|
---|
1183 | return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, hw_dst_addr,
|
---|
1184 | (struct eth_addr *)netif->hwaddr, netif_ip4_addr(netif), ðzero,
|
---|
1185 | ipaddr, ARP_REQUEST);
|
---|
1186 | }
|
---|
1187 |
|
---|
1188 | /**
|
---|
1189 | * Send an ARP request packet asking for ipaddr.
|
---|
1190 | *
|
---|
1191 | * @param netif the lwip network interface on which to send the request
|
---|
1192 | * @param ipaddr the IP address for which to ask
|
---|
1193 | * @return ERR_OK if the request has been sent
|
---|
1194 | * ERR_MEM if the ARP packet couldn't be allocated
|
---|
1195 | * any other err_t on failure
|
---|
1196 | */
|
---|
1197 | err_t
|
---|
1198 | etharp_request(struct netif *netif, const ip4_addr_t *ipaddr)
|
---|
1199 | {
|
---|
1200 | LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_request: sending ARP request.\n"));
|
---|
1201 | return etharp_request_dst(netif, ipaddr, ðbroadcast);
|
---|
1202 | }
|
---|
1203 |
|
---|
1204 | #endif /* LWIP_IPV4 && LWIP_ARP */
|
---|